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Objectives The initial color of a ceramic restoration is determined by the background color. Dental ceramics are great at masking a variety of stains, which helps achieve a natural and beautiful smile. A recent study delved into the effectiveness of CAD/CAM bleach shade ceramics of varying thicknesses in concealing dental discoloration. Material and Methods In this laboratory research, ceramic samples including feldspathic ceramics, lithium silicate ceramics, and zirconia ceramics of varying thicknesses were used. Each type of ceramic had a thickness of 0.5, 1.0, 1.5, and 2.0 mm, with dimensions of 7 × 7 mm (n = 10). Backgrounds of C4 and A2 color porcelain were used. To evaluate color coverage, ceramic pieces were placed on the C4 and A2 porcelain backgrounds, and the Vita spectrophotometer was used to calculate the L*a*b* parameters and color difference (ΔE00). A ΔE00 value of ≤ 1.8 was considered clinically acceptable. The data was analyzed using two‐way and one‐way analysis of variance tests, and pairwise comparisons of groups were performed using Tukey's test. Results The research revealed that both the thickness and type of ceramic material significantly influenced the color changes of the samples, with their interaction also playing a crucial role (all three: p < 0.001). Zirconia demonstrated superior color masking performance on the C4 substrate at 0.5 and 1.0 mm thicknesses. The masking ability of ceramics varied at 0.5, 1.0, and 1.5 mm but notably improved at a thickness of 2.0 mm. Conclusions Zirconia generally demonstrated superior masking ability across all thicknesses, while other ceramics exhibited commendable performance only at 1.5 and 2.0 mm thicknesses. Nevertheless, augmenting the thickness of ceramic restorations amplified their masking capability.

Learn to master the AutoCAD software This Autodesk Official Training guide is a comprehensive reference and tutorial that will help you quickly master AutoCAD software. Featuring concise explanations, step-by-step instructions, and hands-on projects based on real-world designs, this Autodesk Official Training Guide covers everything from interface best practices to hatches, fields, dynamic blocks, attributes, linking drawings to databases, rendering realistic views, and presenting designs. This Mastering book is recommended as a Certification Preparation study guide resource for the AutoCAD Associate and Professional exams. Serves as an in-depth resource on the fundamentals, functions, and features of AutoCAD, the popular 2D and 3D drawing software, and its less expensive version AutoCAD LT Describes how to effectively use hatches, fields, and tables; execute 3D modeling, imaging, and customizing; work with dynamic blocks, drawing curves, and solid fills; and more Features a DVD with more than a dozen video tutorials, \"before and after\" tutorial files, a trial version of AutoCAD, and additional tools and utilities Shares helpful examples, step-by-step instructions, and hands-on projects from award-winning author and CAD specialist George Omura This detailed tutorial is mandatory reading if you're eager to become proficient with AutoCAD or AutoCAD LT.

To date, no study has compared the effects of CAD/CAM versus flexible multistrand wire (FMS) retainers in the presence/absence of root resorption and/or alveolar crestal bone resorption on the anterior mandibular teeth’s stresses/displacements. Therefore, this simulation was conducted. Developed were 8 mandible models with six anterior teeth. Models 1 to 4 had FMS retainers; models 5 to 8 had nickel-titanium CAD/CAM retainers. Models #1 and 5: Both bone and roots were intact; #2 and 6: Only alveolar crests had resorption (2 mm); Models #3 and 7: Only roots had resorption (2 mm); Models #4 and 8: Both the bone and roots were resorbed (each 2 mm). Models were loaded with a vertical force of 187 N. Estimated were their PDL pressures, increased risks of root resorption (defined as PDL stresses > 0.0047 MPa), and 3D tooth movements. Right and left sides were averaged. Scenarios were compared. The present study supports the use of this type of FMS retainer due to less stress, less root resorption risk, and smaller displacements where both root and alveolar crest resorption exist. In terms of PDL stress and root resorption risk of the six anterior teeth, CAD/CAM retainers might act similar to or worse than conventional multistrand retainers (except for lateral incisors in models with crestal bone resorption). CAD/CAM retainers in cases with both crestal and root resorptions might pose a considerably high risk of additional root resorption. For canines and central incisors, the presence of root resorption versus bone resorption might not matter much for increasing their PDL stresses. Nevertheless, for lateral incisors, bone resorption may affect their PDL stresses more than root resorption. FMS might be superior to CAD/CAM in most evaluated scenarios, except few scenarios like intact bone and roots.

Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) and polymethyl methacrylate (PMMA) are used very often in dentistry. Y-TZP is the most widely used zirconia dental ceramic, and PMMA has classically been used in removable prosthesis manufacturing. Both types of materials are commercialized in CAD/CAM system blocks and represent alternatives for long-lasting temporary (PMMA) or definitive (Y-TZP) implantological abutments. The aim of the present work is to reveal that human gingival fibroblasts (HGFs) have a favorable response when they are in contact with Y-TZP or PMMA as a dental implant abutment or implant-supported fixed prosthesis, and also to review their principal characteristics. We conducted an electronic search in the PubMed database. From an initial search of more than 32,000 articles, the application of filters reduced this number to 5104. After reading the abstracts and titles, we reduced the eligible articles to 23. Ultimately, we have included eight articles in this review.

An Autodesk Official Press guide to the powerful mechanical design software Autodesk Inventor has been used to design everything from cars and airplanes to appliances and furniture. This comprehensive guide to Inventor and Inventor LT features real-world workflows and work environments, and is packed with practical tutorials that focus on teaching Inventor tips, tricks, and techniques. Additionally, you can download datasets to jump in and practice on any exercise. This reference and tutorial explains key interface conventions, capabilities, tools, and techniques, including design concepts and application, parts design, assemblies and subassemblies, weldment design, and the use of Design Accelerators and Design Calculators. There's also detailed coverage of design tactics for large assemblies, effective model design for various industries, strategies for effective data and asset sharing, using 2D and 3D data from other CAD systems, and improving designs by incorporating engineering principles. Uses real-world sample projects so you can quickly grasp the interface, tools, and processes Features detailed documentation on everything from project set up to simple animations and documentation for exploded views, sheet metal flat patterns, plastic part design, and more Covers crucial productivity-boosting tools, iLogic, data exchange, the Frame Generator, Inventor Studio visualization tools, dynamic simulation and stress analysis features, and routed systems features Downloadable datasets let you jump into the step-by-step tutorials anywhere Mastering Autodesk Inventor and Autodesk Inventor LT is the essential, comprehensive training guide for this powerful software.

Objectives The aim of this clinical trial was to evaluate the marginal and internal fit of CAD/CAM fabricated zirconia crowns and three-unit fixed dental prostheses (FDPs) resulting from direct versus indirect digitalization. The efficiency of both methods was analyzed. Materials and methods In 25 patients, 17 single crowns and eight three-unit FDPs were fabricated with all-ceramic zirconia using CAD/CAM technology. Each patient underwent two different impression methods; a computer-aided impression with Lava C.O.S. (CAI) and a conventional polyether impression with Impregum pent soft (CI). The working time for each group was recorded. Before insertion, the marginal and internal fit was recorded using silicone replicas of the frameworks. Each sample was cut into four sections and evaluated at four sites (marginal gap, mid-axial wall, axio-occlusal transition, centro-occlusal site) under ×64 magnification. The Mann–Whitney U test was used to detect significant differences between the two groups in terms of marginal and internal fit (α = 0.05). Results The mean for the marginal gap was 61.08 μm (±24.77 μm) for CAI compared with 70.40 μm (±28.87 μm) for CI, which was a statistically significant difference. The other mean values for CAI and CI, respectively, were as follows in micrometers (± standard deviation): 88.27 (±41.49) and 92.13 (±49.87) at the mid-axial wall; 144.78 (±46.23) and 155.60 (±55.77) at the axio-occlusal transition; and 155.57 (49.85) and 171.51 (±60.98) at the centro-occlusal site. The CAI group showed significantly lower values of internal fit at the centro-occlusal site. A quadrant scan with a computer-aided impression was 5 min 6 s more time efficient when compared with a conventional impression, and a full-arch scan was 1 min 34 s more efficient. Conclusions Although both direct and indirect digitalization facilitate the fabrication of single crowns and three-unit FDPs with clinically acceptable marginal fit, a significantly better marginal fit was noted with direct digitalization. Digital impressions are also less time-consuming for the dental practitioner and the patient. Clinical relevance The results show that a direct, intraoral, digitalized impression technique is more accurate and efficient when compared with conventional impressions in fabricating single crowns and three-unit FDPs.

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Objectives Milling is a crucial step in producing restorations using computer-aided design and computer-aided manufacturing (CAD/CAM) systems. In this study the trueness of currently available milling devices was evaluated. Materials and methods Thirty clinical cases (ten inlays, ten crowns, ten onlays) were milled from ceramic blocks using four different milling approaches: five axis with IMES CORiTEC 450i, four axis with CEREC MCXL, four axis with CEREC MCXL-EF and five axis with inLab MCX5. The milled restorations were scanned and the occlusal and inner surfaces compared to the originally calculated 3D surface using difference analysis software. The (90–10 %) / 2 percentile of the distances were calculated and analysed using one-way ANOVA with the post hoc Scheffé test ( α  = 0.05). Chipping of marginal areas were visually examined and analysed using one-way ANOVA with a post hoc Tamhane test ( α  = 0.05). Results At inner surfaces, the milling trueness of IMES (33.9 ± 16.3 μm), X5 (32.3 ± 9.7 μm) and MCXL-EF (34.4 ± 7.5 μm) was significantly better ( p  < 0.001) than that of MCXL (62.1 ± 17.1 μm). At occlusal surfaces, MCXL-EF (25.7 ± 9.3 μm) showed significant higher accuracy ( p  < 0.001) than MCXL (48.7 ± 23.3 μm) and X5 (40.9 ± 20.4 μm). IMES produced the most chipping ( p  < 0.001). Conclusions Five-axis milling devices yield high trueness. MCXL-EF is competitive and may allow chairside fabrication with good milling results. Clinical relevance Accurate milling is required for well-fitting restorations and thereby requires fewer manual finishing steps, yields smaller marginal gaps, resistance to secondary caries and longevity of restorations.

Learn the Essentials on Autodesk's powerhouse architectural softwareThe new Essentials series from Sybex helps you quickly learn and use Autodesk software. This beautiful, task-based, full-color Autodesk Official Training Guide thoroughly covers the fundamentals of AutoCAD and AutoCAD LT. Readers learn how to draw in 2D, shape complex curves, manage objects with layers, organize with blocks and groups, add dimensions and annotation, work with layouts, plot and print, model in 3D, create realistic renderings, and much more.This four-color Essentials book features real-world tutorials, downloadable before-and-after exercise files, and additional suggested exercises. This book is recommended as a Certification Preparation study guide resource for the AutoCAD Associate and Professional exams.Covers AutoCAD 2012 and AutoCAD LT 2012 fundamentals, so you become quickly productive with the softwarePrepares you for the AutoCAD 2012 Associate and Professional certification examUses straightforward explanations and real-world, hands-on exercises and tutorials to teach the software's core features and functionsHelps you develop the skills you'll need throughout a production pipeline, whether you're a beginner or a more experienced user brushing up on the basicsIf you want to learn AutoCAD essentials, AutoCAD 2012 and AutoCAD LT 2012 Essentials is the place to start.